I have a Elecraft KFL3A-400 K3 Filter (8 pole 400Hz) available to swap for a KFL3A-2.1K Filter (8 pole 2.1KHz). The 400Hz filter was already installed in the K3 I recently bought and since I don't do any CW work do not use this filter and would like to swap for one I can use. Pete Damiano W2FGU